The 32nd annual Great American Beer Festival opens today in Denver — or, as it often seems, San Diego brewers’ home away from home.

The three-day event brings together American brewers and their fans for seminars, tastings and the nation’s biggest, most prestigious competition. This year, nearly 5,000 beers will be judged in 84 categories, from A (American-style Wheat Beer) to Z (Zwickelbier, a bubbly, mild brew with German roots).

In this Rocky Mountain scramble for medals, San Diego regularly strikes gold, silver and bronze. Over the past four years, locals have won 63 medals — equal to the combined haul of every brewery in Alabama, Arkansas, Florida, Georgia, Massachusetts, Vermont and Wisconsin.

“If you are in the top three in any category,” said Shawn DeWitt, Coronado Brewing Company’s brewmaster, “that’s a huge honor.”

San Diego beer is undergoing unprecedented growth. Over the next three days, this festival will help answer key questions raised by this period of rapid change.

Are the rookies ready?

In the past year, about 30 new breweries have opened in the county. Some, like Rip Current in San Marcos, will skip this competition.

“I wanted to give us more time to get up and going,” said co-founder Paul Sangster.

Others, like Kearny Mesa’s Societe, wanted to enter but could not — the competition’s online registration closed in less than two hours. (This was not just a rookie error: veterans Alpine Beer and Vista’s Mother Earth also were among those shut out.)

Great American Beer Festival

Dates: Oct. 10-12

Location: Colorado Convention Center, Denver

Attendees: 49,000

Beers available for sampling: 3,000+, the most ever at one event

Beers in competition: 4,875

Breweries in competition: 745

San Diego’s best showing: 18 medals, 2011

Yet a fair number of newcomers did register. They include Solana Beach’s eight-month-old Culture Brewing; and San Diego’s Modern Times and Benchmark, both of which opened in June.

Are they ready for the national spotlight?

“We feel that our beers can stand out among the rest,” said Steve Ragan, Culture’s brewmaster. “What better way to see where you are at in the world of beers than to enter this competition?”

To Modern Times founder Jacob McKean, though, winning or losing is irrelevant: “I really don’t put any stock in awards. But the GABF is an unparalleled opportunity to try new beers and meet other brewers.”

Will Pizza Port extend its streak?

Since 2009, county brewers have averaged almost 16 medals a year here — and many of those wins came when Jeff Bagby led brewing operations for the Pizza Port chain. (Pizza Port’s only venture outside San Diego County, its San Clemente brewpub, also won numerous awards but is not included in local totals.)

But Bagby left that job in 2012 to focus on his own venture, Bagby Beer, which is due to open in Oceanside by year’s end. Yiga Miyashiro, who guided Pizza Port Ocean Beach to the 2011 festival’s Small Brewpub and Small Brewpub Brewer of the Year honors, left this year for fledgling Saint Archer.

Regardless, several rivals predict the Carlsbad-based chain will continue its winning streak.

“If I had to put money on anyone, it would be Pizza Port,” said Jeff Silver, brewer at Mira Mesa’s Rough Draft. “They always do well.”

New Beervanas on horizon?

San Diego is not alone in witnessing a brewery boom. More U.S. breweries and brewpubs operate now than ever: 2,538, a 25 percent increase since 2011.

“With so many more breweries around,” DeWitt said, “it will be a lot more difficult to medal.”

Stone’s Greg Koch warns that some cities — Asheville, N.C., say, or Grand Rapids, Mich. — are eager to supplant San Diego, Portland and Denver as America’s top Beervanas. If other regions surpass San Diego in the medal count, will there be enough beer for locals to drown their sorrows?